The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, lactate, cholesterol and bilirubin should be monitored in certain individuals. In particular, it is important that diabetic individuals frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. The results of such tests can be used to determine what, if any, insulin or other medication needs to be administered.
One non-invasive method for obtaining a sample without using a lancet is to take a transdermal sample of an analyte found in interstitial fluid (ISF). In this method, a composition, such as a hydrogel, is placed on the skin and assists in facilitating diffusion of analytes from a user's skin to a sensing instrument or meter, and in some cases (e.g., glucose) their subsequent products after enzyme-catalyzed reactions. An enzyme in the hydrogel composition assists in determining the analyte concentration of the sample. This composition desirably possesses sufficient mechanical and thermal stability to provide a relatively static, reactive and aqueous contact between the dermal sampling site and sensing instrument. One problem encountered with existing hydrogel compositions is the tendency of the enzyme to leach therefrom. It would be desirable to find a hydrogel composition that addresses such a problem.